1. Field
This document relates to a memory reduction device of a stereoscopic image display for compensating for crosstalk.
2. Related Art
A stereoscopic image display implements a stereoscopic image, i.e., a three-dimensional (3D) image, by using a stereoscopic technique or an autostereoscopic technique. The stereoscopic technique, which uses parallax images of left and right eyes having great stereoscopic effect, includes glass type stereoscopic scheme and a non-glass type stereoscopic technique, both of which have been commercialized.
A glass type stereoscopic image display is divided into a polarization glass type stereoscopic image display and a shutter-glass type stereoscopic image display. The polarization glass type stereoscopic image display includes a polarization splitter, such as a patterned retarder, joined to a display panel. The patterned retarder splits polarized light of a left eye image and a right eye image displayed on the display panel. When enjoying (or viewing) a stereoscopic image through a polarization glass type stereoscopic image display, a viewer (or a user) wears polarization glasses to view polarized light of a left eye image through a left eye filter of the polarization glasses and polarized light of a right eye image through a right eye filter of the polarization glasses, obtaining a three-dimensional (3D) effect.
The shutter-glass type stereoscopic image display, without a polarization splitter attached to a display panel, alternately displays a left eye image and a right eye image on the display panel and opens a left eye shutter of shutter glasses such that it is synchronized with the left eye image and opens right eye shutter of the shutter glasses such that it is synchronized with the right eye image. When viewing a stereoscopic image through the shutter-glass type stereoscopic image display, a viewer wears shutter glasses to view polarized light of a left eye image through the left eye shutter of the shutter glasses and polarized light of a right eye image through the right eye shutter of the shutter glasses, obtaining a 3D effect.
Picture quality evaluation items of a stereoscopic image display include contrast, flicker, 3D crosstalk, and the like, and among them, 3D crosstalk is the biggest issue. 3D crosstalk is a phenomenon by which light (light leakage) of anther eye image is made incident to one eye (right eye or left eye) of a viewer to distort luminance of the one eye image. 3D crosstalk is severely appears in the shutter-glass type stereoscopic image display in which left eye images and right eye images are alternately displayed at certain timer intervals, but it is also problematic even with the polarization glass type stereoscopic image display in which left eye images and right eye images are simultaneously displayed separately by the line.
Recently, in order to compensate for 3D crosstalk, a technique of predicting a portion in which crosstalk is generated by comparing left eye and right eye images displayed to neighbor to each other temporally (or spatially), and modulating data of the predicted portion with a compensation value has been proposed by the applicant of this application. As illustrated in FIG. 1, this technique compensates for 3D crosstalk by using a crosstalk compensation unit 1 comparing Gn−1 to be displayed to neighbor to each other temporally (or spatially) and modulating Gn into Gn′ and a memory 2 storing Gn−1 for a certain period of time. Gn, any one of left eye data and right eye data, indicates frame (or line) data to be displayed in nth frame (or nth horizontal pixel line), and Gn−1, the other of the left eye data and the right eye data, indicates frame (or line) data to be displayed in (n−1)th frame (or (n−1)th horizontal pixel line). The crosstalk compensation unit 1 is implemented as a look-up table from which the compensation value Gn′ is read by using Gn and Gn−1 as read addresses.
In this case, however, in order to implement a 3D crosstalk compensation technique, a large capacity memory is required. When red data (R), green data (GL), and blue data (GL) for image implantation are comprised of 8 bits, respectively, an existing 3D crosstalk compensation technique requires a memory having a capacity of about (horizontal resolution*3*8*2) bits although it is applied to a polarization glass type. For example, in case of applying the existing 3D crosstalk compensation technique to a polarization glass-type stereoscopic image display implementing FHD resolution, a required capacity of a memory amounts to (1920*3*8*2=92160 bit)(=11.25 KByte). When the existing 3D crosstalk compensation technique is applied to the shutter-glass type stereoscopic image display, a required capacity of a memory is further increased.